/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */
(function () {

// Shortcut
    var util = Crypto.util;

// Precomputed SBOX
    var SBOX = [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
        0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
        0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
        0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
        0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
        0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
        0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
        0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
        0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
        0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
        0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
        0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
        0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
        0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
        0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
        0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
        0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
        0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
        0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
        0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
        0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
        0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
        0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
        0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
        0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
        0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
        0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
        0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
        0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
        0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
        0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
        0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16];

// Compute inverse SBOX lookup table
    for (var INVSBOX = [], i = 0; i < 256; i++) INVSBOX[SBOX[i]] = i;

// Compute mulitplication in GF(2^8) lookup tables
    var MULT2 = [],
        MULT3 = [],
        MULT9 = [],
        MULTB = [],
        MULTD = [],
        MULTE = [];

    function xtime(a, b) {
        for (var result = 0, i = 0; i < 8; i++) {
            if (b & 1) result ^= a;
            var hiBitSet = a & 0x80;
            a = (a << 1) & 0xFF;
            if (hiBitSet) a ^= 0x1b;
            b >>>= 1;
        }
        return result;
    }

    for (var i = 0; i < 256; i++) {
        MULT2[i] = xtime(i, 2);
        MULT3[i] = xtime(i, 3);
        MULT9[i] = xtime(i, 9);
        MULTB[i] = xtime(i, 0xB);
        MULTD[i] = xtime(i, 0xD);
        MULTE[i] = xtime(i, 0xE);
    }

// Precomputed RCon lookup
    var RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36];

// Inner state
    var state = [[], [], [], []],
        keylength,
        nrounds,
        keyschedule;

    var AES = Crypto.AES = {

        /**
         * Public API
         */

        encrypt: function (message, password, mode) {

            var

            // Convert to bytes
                m = util.stringToBytes(message),

            // Generate random IV
                iv = util.randomBytes(AES._blocksize * 4),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {asBytes: true});

            // Determine mode
            mode = mode || Crypto.mode.OFB;

            // Encrypt
            AES._init(k);
            mode.encrypt(AES, m, iv);

            // Return ciphertext
            return util.bytesToBase64(iv.concat(m));

        },

        decrypt: function (ciphertext, password, mode) {

            var

            // Convert to bytes
                c = util.base64ToBytes(ciphertext),

            // Separate IV and message
                iv = c.splice(0, AES._blocksize * 4),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {asBytes: true});

            // Determine mode
            mode = mode || Crypto.mode.OFB;

            // Decrypt
            AES._init(k);
            mode.decrypt(AES, c, iv);

            // Return plaintext
            return util.bytesToString(c);

        },


        /**
         * Package private methods and properties
         */

        _blocksize: 4,

        _encryptblock: function (m, offset) {

            // Set input
            for (var row = 0; row < AES._blocksize; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] = m[offset + col * 4 + row];
            }

            // Add round key
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] ^= keyschedule[col][row];
            }

            for (var round = 1; round < nrounds; round++) {

                // Sub bytes
                for (var row = 0; row < 4; row++) {
                    for (var col = 0; col < 4; col++)
                        state[row][col] = SBOX[state[row][col]];
                }

                // Shift rows
                state[1].push(state[1].shift());
                state[2].push(state[2].shift());
                state[2].push(state[2].shift());
                state[3].unshift(state[3].pop());

                // Mix columns
                for (var col = 0; col < 4; col++) {

                    var s0 = state[0][col],
                        s1 = state[1][col],
                        s2 = state[2][col],
                        s3 = state[3][col];

                    state[0][col] = MULT2[s0] ^ MULT3[s1] ^ s2 ^ s3;
                    state[1][col] = s0 ^ MULT2[s1] ^ MULT3[s2] ^ s3;
                    state[2][col] = s0 ^ s1 ^ MULT2[s2] ^ MULT3[s3];
                    state[3][col] = MULT3[s0] ^ s1 ^ s2 ^ MULT2[s3];

                }

                // Add round key
                for (var row = 0; row < 4; row++) {
                    for (var col = 0; col < 4; col++)
                        state[row][col] ^= keyschedule[round * 4 + col][row];
                }

            }

            // Sub bytes
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] = SBOX[state[row][col]];
            }

            // Shift rows
            state[1].push(state[1].shift());
            state[2].push(state[2].shift());
            state[2].push(state[2].shift());
            state[3].unshift(state[3].pop());

            // Add round key
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] ^= keyschedule[nrounds * 4 + col][row];
            }

            // Set output
            for (var row = 0; row < AES._blocksize; row++) {
                for (var col = 0; col < 4; col++)
                    m[offset + col * 4 + row] = state[row][col];
            }

        },

        _decryptblock: function (c, offset) {

            // Set input
            for (var row = 0; row < AES._blocksize; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] = c[offset + col * 4 + row];
            }

            // Add round key
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] ^= keyschedule[nrounds * 4 + col][row];
            }

            for (var round = 1; round < nrounds; round++) {

                // Inv shift rows
                state[1].unshift(state[1].pop());
                state[2].push(state[2].shift());
                state[2].push(state[2].shift());
                state[3].push(state[3].shift());

                // Inv sub bytes
                for (var row = 0; row < 4; row++) {
                    for (var col = 0; col < 4; col++)
                        state[row][col] = INVSBOX[state[row][col]];
                }

                // Add round key
                for (var row = 0; row < 4; row++) {
                    for (var col = 0; col < 4; col++)
                        state[row][col] ^= keyschedule[(nrounds - round) * 4 + col][row];
                }

                // Inv mix columns
                for (var col = 0; col < 4; col++) {

                    var s0 = state[0][col],
                        s1 = state[1][col],
                        s2 = state[2][col],
                        s3 = state[3][col];

                    state[0][col] = MULTE[s0] ^ MULTB[s1] ^ MULTD[s2] ^ MULT9[s3];
                    state[1][col] = MULT9[s0] ^ MULTE[s1] ^ MULTB[s2] ^ MULTD[s3];
                    state[2][col] = MULTD[s0] ^ MULT9[s1] ^ MULTE[s2] ^ MULTB[s3];
                    state[3][col] = MULTB[s0] ^ MULTD[s1] ^ MULT9[s2] ^ MULTE[s3];

                }

            }

            // Inv shift rows
            state[1].unshift(state[1].pop());
            state[2].push(state[2].shift());
            state[2].push(state[2].shift());
            state[3].push(state[3].shift());

            // Inv sub bytes
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] = INVSBOX[state[row][col]];
            }

            // Add round key
            for (var row = 0; row < 4; row++) {
                for (var col = 0; col < 4; col++)
                    state[row][col] ^= keyschedule[col][row];
            }

            // Set output
            for (var row = 0; row < AES._blocksize; row++) {
                for (var col = 0; col < 4; col++)
                    c[offset + col * 4 + row] = state[row][col];
            }

        },


        /**
         * Private methods
         */

        _init: function (k) {
            keylength = k.length / 4;
            nrounds = keylength + 6;
            AES._keyexpansion(k);
        },

        // Generate a key schedule
        _keyexpansion: function (k) {

            keyschedule = [];

            for (var row = 0; row < keylength; row++) {
                keyschedule[row] = [
                    k[row * 4],
                    k[row * 4 + 1],
                    k[row * 4 + 2],
                    k[row * 4 + 3]
                ];
            }

            for (var row = keylength; row < AES._blocksize * (nrounds + 1); row++) {

                var temp = [
                    keyschedule[row - 1][0],
                    keyschedule[row - 1][1],
                    keyschedule[row - 1][2],
                    keyschedule[row - 1][3]
                ];

                if (row % keylength == 0) {

                    // Rot word
                    temp.push(temp.shift());

                    // Sub word
                    temp[0] = SBOX[temp[0]];
                    temp[1] = SBOX[temp[1]];
                    temp[2] = SBOX[temp[2]];
                    temp[3] = SBOX[temp[3]];

                    temp[0] ^= RCON[row / keylength];

                } else if (keylength > 6 && row % keylength == 4) {

                    // Sub word
                    temp[0] = SBOX[temp[0]];
                    temp[1] = SBOX[temp[1]];
                    temp[2] = SBOX[temp[2]];
                    temp[3] = SBOX[temp[3]];

                }

                keyschedule[row] = [
                    keyschedule[row - keylength][0] ^ temp[0],
                    keyschedule[row - keylength][1] ^ temp[1],
                    keyschedule[row - keylength][2] ^ temp[2],
                    keyschedule[row - keylength][3] ^ temp[3]
                ];

            }

        }

    };

})();
